I show how to tighten or loosen nuts and bolts when you don’t have the correct size wrench. When the wrench is too large for the nut or bolt you can use some coins or washers to fill the extra space between the nut or bolt and the wrench.
Try to pick a wrench that is the closest size to the bolt and try different combinations of coins to get a snug fit. If the wrench is too small you can take a long nut and a bolt, screw the nut onto the bolt and tighten the bolt around the nut you want to tighten or loosen.
You can also use shorter bolts and a small wrench for leverage. Although this can be useful for some applications I would not recommend using this to replace wrenches of correct sizes or use on motor vehicles.